1. Field of the Invention
The present invention relates to a battery controller, and more particularly, to a built-in battery controller for a personal telecommunication device.
2. Description of the Related Art
When a personal telecommunication device including a built-in battery, such as a cellular phone or personal digital assistant (PDA) is delivered from a factory to a customer, the built-in battery must be kept in a complete off state. However, it is often complex to turn on the built-in battery from the complete off state. Since the battery has been built in the personal telecommunication device and turned off at the factory, the customer is required to disassemble the personal telecommunication device, turn on the battery, and reassemble the device. To solve this problem, the battery can be equipped with a switch that can be operated from the outside. However, since the size of such outside switch is relatively large, the battery is not conducive to use in a modern telecommunication device requiring a slim design.
FIG. 1 is a schematic diagram of a related art battery controller. As shown in FIG. 1, the controller 100 includes a battery 110 and a slide switch 120 for switching on/off the battery 100. The slide switch 120 is directly connected to the battery 100. In this type of controller, since the slide switch 120 directly controls the battery 110, a relatively strong and large mechanical switch is used as the slide switch 120. Further, such a relatively large mechanical switch capable of enduring high currents is placed outside of a set, e.g., a telecommunication device. The slide switch 120 is switched off at the factory and is switched on when a customer obtains and operates the set. Since a relatively large slide switch is placed outside of a set, the controller 100 shown in FIG. 1 is not adequate for use in a modern personal telecommunication device, such as a PDA, having a slim size.
FIG. 2 is a schematic diagram of another type of related art battery controller. The battery controller 200 shown in FIG. 2 includes a battery 210, a Field Effect Transistor (FET) 220 for controlling on/off operations of the battery 210, and a slide switch 230 for controlling the FET 220. The FET 220 is fairly small in comparison with a mechanical switch and is placed within a set. Further, since the function of the slide switch 230 is to control the FET 220, a fairly small slide switch can be used and placed outside of a set in comparison with a mechanical switch used in the controller 100 shown in FIG. 1. When the slide switch 230 is switched off at the factory, the FET 220 is turned off and thus the battery 210 is turned off. When a customer switches on the slide switch 230, the FET 220 connected to the slide switch 230 is turned on, and thus, the battery 210 is turned on. The controller 200 shown in FIG. 2 is advantageous from the viewpoint of design since a fairly small slide switch can be used. However, since power is continuously applied to the FET switch 220, the FET switch 220 can be damaged, and if the FET 220 is damaged, the battery 210 may not be kept in the off state. In this event, an accidental problem may occur during shipment.
Since the switch to turn off and on the battery is used only once until a customer purchases the set including the battery, it is important to design the outer appearance of the set such that the switch is not too noticeable. Further, since the purpose of turning off the battery is to prevent an accident during distribution, it is important to surely turn off the battery.